Thoughts on the Sig Adaptive Carbine Platform (ACP)?

Looks like an interesting home defense option. Sounds like it lives in an ATF grey area, which makes me kind of nervous. I think it would be a fun one to throw a Glock 10mm in! Anyone have an experience with it?

Looks like an interesting home defense option. Sounds like it lives in an ATF grey area, which makes me kind of nervous. I think it would be a fun one to throw a Glock 10mm in! Anyone have an experience with it?

I was referencing a review on the item from thetruthaboutguns.com. He was discussing how easy it would be to get yourself in trouble with the ability to add fore grip on the provided rail, or a stock. In either case it would need to be registered with the ATF (according to him). Where it got fuzzy was when it came to which piece you would register in the event you added one of those items.

the question is still open as to what part actually carries the NFA registered serial number. The ACP frame itself isn&#8217;t serialized, so do you engrave a serial number on the ACP itself or do you register the serial number of the host pistol? Chances are no one at the ATF will have the stones to go on record to answer this question definitively, which means you choose one or the other and then patiently await your arrest and court date.

That was an excerpt from the article, he goes on to pose the question of changing the pistol you use, and whether you could legally do that or would need to register the change.

And not to pick at it (and this may not be an example), but after 6 years in the military, I can assure you that that all government bureaucracies have grey areas.

Then almost every modern pistol would be in a "grey" area since most have rails on them and can easily have a VFG added. Glock also has stock that drops right on, again no issues or ATF worries.

There is no waiting for your "arrest date" you fill out and submit your forms for the NFA item. Once it come back APPROVED then you build you LEGAL item. Depending on the gun will depend on the "part" registered. In most cases it is the receiver but in some cases I have seen the barrels registered in the case of SBR/SBS. This is not a reinvention of the wheel, new NFA items have been made for a long time and it just requires proper registration.

Then almost every modern pistol would be in a "grey" area since most have rails on them and can easily have a VFG added. Glock also has stock that drops right on, again no issues or ATF worries.

There is no waiting for your "arrest date" you fill out and submit your forms for the NFA item. Once it come back APPROVED then you build you LEGAL item. Depending on the gun will depend on the "part" registered. In most cases it is the receiver but in some cases I have seen the barrels registered in the case of SBR/SBS. This is not a reinvention of the wheel, new NFA items have been made for a long time and it just requires proper registration.

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That's why you get a mechtech... no registration required.
Swap back and forth all you want without involving uncle sam.

As to the question of what part to register I am not sure. I would think you could do the ACP itself. There was another company making a similar product but I can not recall the name. I would see how they are dealing with NFA issues.

It's not actually an option to add a stock. The version with a stock is a separate item and is the only item that requires ATF registration.

The mechtech is crap built around a pistol lower with a built-on collapsible stock. The only real difference is that one replaces the factory slide and bbl, the other attaches to them.
The sig version requires ATF paperwork whereas the mechtech does not.

They're not exactly the same, but in terms of overall concept they're pretty damned close.

the acp is not the firearm the pistol you are putting into the acp is and is the part that will need to be registered with atf as an sbr if you are running the stock version.......... another interesting variant is converting the acp to use the folding ace stock

If you want to go from pistols to PDW/carbine, assuming it was legal to do so, why.

I think if you have your handgun, decide you need the ACP, instead of putting that on your handgun, just grab a ready to go PDW/carbine, in WA you could grab your 8.2" 300 BLK pistol, you lucky bastards in OR and ID, can get your SBR.

No but per the ATF there is no such thing legally as a Carbine if you want to get technical. There are Title 1 firearms consisting of "long gun", "hand gun", and now "other" for things like receivers. There are Title 2 firearms that consist of SBR, SBS, DD, AOW, MG and Silencers.

The Mechtech takes a Title 1 "handgun" and legally makes into a Title 1 "long gun". The ACP (no matter what the letters stand for) turns you Title 1 "handgun" into a bulkier version or you would have the option of going Title 2 and making either an AOW or SBR depending on what features you add. I see no option listed on their site for turning it into a Title 1 "long gun".

For me that is where the big difference is. Mechtech = only Title 1, ACP = bulky handgun or NFA.

For me that is where the big difference is. Mechtech = only Title 1, ACP = bulky handgun or NFA.

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They're both the exact same thing- a piece of metal made to hold a handgun. The Mech comes with a longer barrel to make it title 1, but could be cut down for SBR. The ACP comes with no barrel and would be SBR with a stock, no saying you couldn't figure out a way to attempt to make 16".

The gun would be the registered item if choose to do so. I've never registered my Magpul UBR for ANY of my SBR's I've done.

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